<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>用border增加点击区域</title>
    <style>
        div{
            font-size: 16px;
            width:16px;
            height:16px;
            /*background-color: fuchsia;*/
            border:100px solid transparent;
        }
    </style>
</head>
<body>
<div>
X
</div>
<script>
    var oDiv=document.querySelector("div");
    oDiv.onclick=function(){
        alert(1);
    }
</script>
</body>
</html>